Circuit interrupter



July 16, 1940.

Ihwentor 2g GeOr e IV Lemmon F 1' 5 3 W y gjg July 16, 1940. 1 LEMMQN 2,208,099

CIRCUIT INTERRUPTER Filed July 9, 1938 2 Sheets-Sheet. 2

Snventor Geor e Lemma Patented July 16, 1940 UNITED STATES PATENT OFFICE CIRCUIT INTERRUPTER George N. Lemmon, Birmingham, Ala,

to Southern assignor States Equipment Corporation, a

10 Claims.

This invention relates to circuit interrupters, and has for an object the provision of apparatus of the character designated in which a fuse is held in tension by members which are biased to move apart when the fuse ruptures and interpose a wide air gap, thereby preventing arcing.

A further object of my invention is to provide a circuit interrupter in which the fuse is supported between arms, at least one of which is biased to hold the fuse in tension, and which shall include means whereby the fuse may be readily inserted in service position.

A still further object of my invention is to provide a circuit interrupter embodying resilient arms between which the fuse is positioned and which are adapted, upon rupture of the fuse, to separate and move to wide open position, and which shall include means to latch either one or both'of the arms away from full open position in order to facilitate the insertion of a fuse between the arms in service position.

A device embodying features of my invention is illustrated in the accompanying drawings forming a part of this application, in which Fig. l is a view in elevation of my improved circuit interrupter, and shows the resilient arms in service position, with their latched positions and wide open positions shown in dotted lines;

Fig. 2 is a sectional View taken along the line II--II of Fig. 1;

Fig. 3 is a detail plan view of one of the resilient arms employed with my invention;

Fig. 4 is a detail view of a fuse element employed with my invention; and

3, Figs. 5, 6, and '7 are detail forms of a guide and with my invention.

Referring to the drawings for a better understanding of my invention, my improved device embodies twin insulators l0 and H having a supporting arm l2, which may be secured by any appropriate means to a frame member it of any suitable mounting apparatus. Mounted on the opposite ends of the insulators IE3 and II are yokes I4, each having a base it by which it is attached to its associated insulator by means of bolts I! and I8. Each of the yokes has formed integrally therewith an arm 19 carrying a line clamp 2|, to which the respective electric circuit lines 22 and 23 are connected.

Also connected to the opposite ends of the insulators l0 and H, by means of the bolts i7 and I8, are resilient arms 24 and 26, each of which is comprised of spring wire having good 55. electrical conducting properties and coiled at 21,

views of modified holding member employed as shown in Fig. 3, whereby when secured as shown in Fig. 1, they tend to take the extreme dotted positions shown in Figs. 1 and 2, and resist being pulled to the full line positions shown in Fig. 1. The resilient arms 24 and 26 preferably are formed It will be apparent, however, that each may be formed from a single wire of the proper strength and resiliency.

In service, there is positioned between the members 24 and 28 a fuse which may comprise a cartridge 3!, and a fusible element 32 within the cartridge. Joined to the fusible element at the bottom is a flexible wire 33 connected to a resilient hook 34, which is adapted to hook about the out-turned portion 29 of arm 26. The resilient hook prevents a chattering connection and is preferably formed by twisting the end of a piece of spring wire to form a ring 35 with the hook 34 formed as shown. Connected to the upper end 29 of the upmovement of the arms 24 and 26. gaged by the shoulders 38, the arms 24 and 25, being resilient, assume the positions shown in full lines and in the outer dotted lines in 2 of the drawings, depending upon whether there is a fuse in position between the arms or not.

The operation of the apparatus is as follows: Assuming no fuse in position and the arms 24 and 26 in their extreme outer dotted position, as shown in Fig. 1, in order to insert a fuse between the arms, the upper down by means of a switch stick, or other suitably insulated tool, and is moved to one side until it engages either one of the shoulders 38, as shown in the lower dotted position of Fig. 2. The lower arm 26 is likewise pushed upwardly the lower resilient of the fusible element 32 is a similar hook element 36 adapted to When not en- 1 arm is first pulled and it is engaged with one of the shoulders 38, the position of the lower yoke l4 and the arm 2'6 being simply reversed from the showing of Fig. 2. The arms are now in the intermediate positions shown in dotted lines in Fig. 1. The switch stick is next inserted in the ring 31 of the fuse link, and the lower hook 34 is hooked about the lower resilient arm 26. The arm 26 is then pushed upwardly by means of the switch stick and the fuse link until the hook element 36 at the upper end ofthe fuse can be hooked about the out-turned portion 29 of the resilient arm 24. During the insertion of the fuse link, it will be seen that there is a greater strain on the lower arm 26 than on the upper arm 24, the arm 26 being released from the shoulder 38 and pulled upwardly as seen in the drawings to a position near the bottom of the yoke it. When the switch stick is then released from the fuse, the arms assume the service position centrally of the yokes l4 shown in full lines in Fig. 2 of the drawings, it being understood that the lower yoke I4 is inverted with respect to the upper yoke and that the positions of the parts at the lower end will be inverted relative to the upper arm 24 and yoke I4.

Assuming now that the fuse 32 ruptures for any reason, the resilient arms 24 and 26 immediately move to the extreme outer positions shown in dotted lines in Fig. l, whereupon they are stopped by the ends of the yoke It, as shown in the upper dotted line position of Fig. 2. The outer ends of the yokes thus serve to prevent the resilient arms from moving too far and perhaps engaging other conductors or surrounding equipment; The initial torsional strain on the arms 24 and 2B is such that they are still under torsional strain when they strike the top of the yoke I l.

Referring now to Fig. a modified form of yoke at one side pivoted at 42, and having an outwardly extending arm 43 which may be engaged by a switch stick to move the latch to the full. line 5 of the drawings, I show 40 having a latch 4i holding position shown in Fig. 5, or to the dotted release position shown. The pivot joint 42 is a tight friction fit so that the latch member 4| r-etains whatever position in which it is placed, and can not accidentally fall in the path of the resilient arm 24. Stop members 44 at the top and 65 at the bottom act to prevent over travel of the latch member.

With the form of yoke just described, whenever it is desired to replace a fuse the latch member is moved to the holding position shown in Fig. 5, and the resilient arm is hooked under it as shown in Fig. 5. After the arm is released by the replacing of a fuse, the latch is moved to the dotted release position by means of the switch stick.

In Fig. 6, I show a further modified form of yoke il which is open at its outer end and has outwardly flaring sides 48 which serve to guide the resilient arms when pulled inwardly. The yoke M is provided with side shoulders 38 similar to those shown in the yoke M in Fig. 2. In all other respects the yoke ll is similar to the yoke In Fig. '7, I show a still further modified form of yoke member 49 formed from bent bus wire.

The yoke 49 is provided with a shoulder 5!;

adapted to engage the resilient arm with which it is associated when replacing a fuse and is also provided with an outer hook 52 which acts as a stop for the resilient arm when a fuse is ruptured.

One side of the yoke member 49 may be left open, as shown in Fig. '7, in accordance with this modification.

From the foregoing it will be apparent that I have devised an improved circuit interrupter embodying resilient arms adapted to move apart and discharge the fuse elements upon rupture thereof and which embodies means whereby the resilient arms may be releasably held in position whereby to mount a fuse between them and be prevented from moving too far apart upon rupture of the fuse.

While I have shown my invention in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. In a circuit interrupter, two spaced insulated supports, an arm extending from each support, at least one of said arms being biased away from its closed-circuit position, a fusible link held in tension in circuit-closing position between the two arms, together with stationary means independent of the said fusible link adapted to be engaged by and to hold the said biased arm under tension relatively near its closed-circuit position. M"

2. In a circuit interrupter embodying spaced insulated resilient arms for holding a fusible element in circuit between them when in service position and disposed to move apart when not so constrained, means for holding at least one of the arms temporarily near its service position, a fuse member embodying elements at its ends for engaging the resilient arms, and means operable by mounting the fusible element to free the arm temporarily held near its service position.

3. In a, circuit interrupter embodying spaced insulated resilient'arms for holding a fusible element in circuit between them when in service position and disposed to move apart when not so constrained, a guide member associated with at least one of the resilient arms and providing a path therein through which said arms moves and is guided in operation, means in the said member to limit outward movement of the arm, and a shoulder on the said guide member to hold the arm temporarily near its service position.

4. In a circuit interrupter, two spaced insulated supports, spring circuit closer arms mounted in spaced relation on said supports, means com prising a fusible element to connect said arms in tension, means to latch at least one of said arms under partial tension, and a current lead connected to each arm, the said circuit closer arm being automatically releasable from the latch means by increasing the tension on the circuit closer arm.

5. In a circuit interrupter, two spaced insulated supports, spring circuit closer arms mounted in spaced relation on said supports, a current lead connected to each arm, means comprising a fusible element to connect said arms'in ten-' sion, and means to latch at least one of said arms under partial tension comprising a yoke with a lateral latch shoulder displaced from the normal path of travel of the circuit closer arm when the latter is released by the fusing of the element connecting said arms.

6. In a circuit interrupter, two spaced insu-' lated supports, spring circuit closer arms mounted in spaced relation on aid supports, a current lead connected to each arm, means comprising a fusible element to connect said arms in tension, and means to latch at least one of said arms under partial tension comprising a closed yoke having side detents adapted to form the latch means, said detents being displaced from the path of travel from said arm when released by the fusing of said connector element.

'7. In a circuit interrupter, two spaced insulated supports, spring circuit closer arms mounted in spaced relation on said supports, a current lead connected to each arm, means comprising a fusible element to connect said arms in tension, and means to latch at least one of said arms under partial tension comprising an elongated yoke adapted to form a stop for the arm when it reaches its extreme release position.

8. In a circuit interrupter embodying spaced insulated resilient arms between which a fusible member is held in tension when the arms are in service position, guide means for at least one of the arms, means disposed to one side of the normal path of travel of the resilient arm and adapted to be engaged by and to hold said arm in a tensioned position temporarily near its service position, and circuit connections to each of the arms,

9. In a circuit interrupter embodying spaced insulated resilient arms between which a fusible member is held in tension when the arms are in service position, guide means for each of the arms, means adapted to be engaged by the independent motion of each arm to hold each of the arms in a temporary tensioned position preparatory to inserting a fusible member, and a circuit connection to each of the resilient arms.

10. In a circuit interrupter embodying spaced insulated resilient arms between which a fusible member is held in tension when the arms are in service position, guide means for each of the arms, means to latch each of the arms in an intermediate position near its service position while inserting a fusible member, a circuit connection to each of the resilient arms, a conducting link comprising a fusible element for connecting the resilient arms, a contact hook on at least one end of the link, and ring means beyond the hook to engage the link to mount it in tension between the resilient arms.

GEORGE N. LEMMON. 

